Wood stair tread over concrete

I have an old house and I'm slowly working on finishing the basement. The problem is the bottom two steps in the basement are poured concrete. It actually works out, that if I lay a wood tread on top of the concrete treads, that the height for my new stairway will work out perfectly.

The question is how can I go about attaching an untreated wood stair tread to a cement tread? I know untreated wood isn't supposed to come into direct contact with wood. Can I coat the cement with something? What about applying something to the back side of the wood tread to "treat" it? I have also wondered about maybe using tar paper or something between the two, but that might bring up an issue when I go to attach the wood tread.

My last resort is to simply try to break out the cement steps, but that really is a last resort.... I have also thought about buying 2"x10" treated lumber and planing it down to 1" thick and using that for my tread, but wonder how "funny" that might look stained....

This may be a little off the wall, but what about using some ice and water shield as is used on a roof? Any fasteners you put through it would be sealed, and it would prevent squeaks or grinding noises if the wood moved against the concrete. Hassle is, a whole roll of the stuff is kind of expensive to only use a little bit. the hassle with wood on concrete is that concrete can wick moisture and create problems with untreated wood. if you isolate it from the wood, you should eliminate that problem.

That sounds like a great idea. I just got back from the lumer yard and they had a product designed to flash windows and doors, that sticks to itself and it'll stick to masonry. I'm guessing it's the same type of product. A roll 6"x100' was only about $25, so that isn't too bad. It's supposed to be a moisture barrier....

Yes, it's probably the same stuff. The rolls for roofing are 4' wide and fairly long...a lot of material you wouldn't need. It's REALLY sticky, once it touches something, it is going to stay, so be careful.

Yes, it's probably the same stuff. The rolls for roofing are 4' wide and fairly long...a lot of material you wouldn't need. It's REALLY sticky, once it touches something, it is going to stay, so be careful.

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Haven't having ever actually worked with this stuff myself, do you know of anything that might stick to this stuff that would allow me to "glue" the treads to this type of material? I am pretty certain I will be able to toenail the tread to the stringer, but in order to safely secure the treads, I'd like to be able to attach them with more than a few toenails. Basically, I guess I'm asking will a construction adhesive stick to the membrane? ...if so any suggestions on type?

I could predrill and countersink some tapcons, but I really don't want to see a a half dozen plugged holes on these treads. I might be able to hide that type of attachment, by adding a skirt board, but won't actually know until I dig in, so it'd be nice to have options.

The stuff is resilient, so it would take something resilient to stick to it. Don't know of anything off the top of my head that would work. You could counterbore and then plug the holes if you wanted to use some Tapcons. A counterbore bit isn't very expensive, and you'll likely have some extra from the tread, so the grain would match well. I don't think you'd really need more than 4, two at each end unless the step was uneven. You could try some contact cement, but it might disolve the stuff. You've got some to spare, so you could try. But, that bond might not survive the expansion/contraction of the wood over season changes. Just don't know.

That's kind of what I thought about finding something to stick to it and then sticking to the wood. I have a counterbore bit, so I guess I'll have to live with that. Better than nothing I suppose... I believe there might be some wobble, but I think I can shim to fix that!